Magnetic in-body and on-body antennas operating at 40MHz and near field magnetic induction link budget

Magnetic antennas are supposed to be less perturbed than electrical antennas in the presence of human body. In this study, initially transmitter spiral coil ingestible capsule (in-body) antenna and receiver magnetic square coil (on-body) antenna have been designed separately at 40MHz with a matching system. Then, a near field magnetic induction link budget has been established in the presence of a human body model. The efficiency (received power/transmitted power) of the magnetic induction link is found to be better than that of an electromagnetic link when both TX and RX antennas are opposite to each other. This phenomenon facilitates to minimize the power consumption and hence to increase the battery life of the wireless capsule. Furthermore, we observe that the magnetic link is efficient enough when the TX antenna, located at any position is randomly oriented while RX antenna is oriented horizontally and vertically to the human body surface.